An overview of industrial motor control systems:
This overview of industrial motor controls highlights the differences and subsystems for DC motor, brushless DC, and AC induction motors. An in-depth analysis of critical subsystems focuses on monitoring and measuring current; sensing temperature; sensing motor speed, position, and movement; monitoring and controlling multichannel currents and voltages; and high-accuracy motor control with encoder data interfaces.
The above application note may be applicable to the recent thread on Controlling Air-Core gauges, particularly the following:
Incremental information is typically transmitted to the controller by quadrature signals, i.e., two signals phase shifted by 90°. These signals can be in analog form (sine + cosine) or in binary form. Absolute position information, in contrast, is only communicated by a serialized binary data stream through RS-482 or RS-422.
Thanks for the tip rsdio!